> is there a possibility to copy an element into another 
> namespace with means
> of <xsl:copy-of> ?

No, you have to use

  ...
  <xsl:element name="{local-name()}">
    ...

If you want a "copy" in null-namespace.

Cheers,

Jarno - Aghast View: Fieldlights

 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list